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Using various latest cosmological datasets including Type-Ia supernovae, cosmic microwave background radiation, baryon acoustic oscillations, and estimations of the Hubble parameter, we test some dark energy models with parameterized…

Cosmology and Nongalactic Astrophysics · Physics 2022-12-28 Jing Yang , Xin-Yan Fan , Chao-Jun Feng , Xiang-Hua Zhai

The current paper provides a comprehensive examination of a dark energy cosmological model in the classical regime, in which a generic scalar field is regarded as a dark energy source. Einstein's field equations are solved in model…

General Relativity and Quantum Cosmology · Physics 2022-09-07 Ritika Nagpal , Shibesh Kumar Jas Pacif , Abhishek Parida

We investigate the cosmological implications of a generalized total equation of state (EoS) model by constraining its parameters using observational datasets to effectively characterize the universe's expansion history and its dynamic…

Cosmology and Nongalactic Astrophysics · Physics 2025-01-14 M. Koussour , S. Bekov , A. Syzdykova , S. Muminov , I. Ibragimov , J. Rayimbaev

This paper explores the dark energy phenomenon within the context of $f(R,L_m)$ gravity theory. Two specific non-linear $f (R, L_m)$ models are considered: $f(R,L_m)=\frac{R}{2}+L_m^\alpha$ and $f(R,L_m)=\frac{R}{2}+(1+\alpha R)L_m$, where…

Cosmology and Nongalactic Astrophysics · Physics 2023-12-13 S. Myrzakulova , M. Koussour , N. Myrzakulov

We consider a general dark energy (DE) model parametrized by its equation-of-state (EoS), featuring three free parameters: $w_0$ (the present-day value of the DE EoS), $w_{\beta}$ (quantifying the dynamical nature of the DE EoS), and…

Cosmology and Nongalactic Astrophysics · Physics 2026-03-24 Dong Ha Lee , Weiqiang Yang , Eleonora Di Valentino , Supriya Pan , Carsten van de Bruck

We reconsider the holographic dark energy (HDE) model with a slowly time varying $ c^2(z)$ parameter in the energy density, namely $\rho_D=3M_p^2 c^2(z)/L^2$, where $L$ is the IR cutoff and $z$ is the redshift parameter. As the system's IR…

General Physics · Physics 2017-06-06 A. Sheykhi , S. Ghaffari , N. Roshanshah

A generally parameterized equation of state (EOS) is investigated in the cosmological evolution with bulk viscosity media modelled as dark fluid, which can be regarded as a unification of dark energy and dark matter. Compared with the case…

Astrophysics · Physics 2009-11-13 J. Ren , Xin He Meng

Are geometrical summaries of the CMB and LSS sufficient for estimating cosmological parameters? And how does our choice of a dark energy model impact the current constraints on standard cosmological parameters? We address these questions in…

Cosmology and Nongalactic Astrophysics · Physics 2009-03-17 Rahul Biswas , Benjamin D. Wandelt

The possibility of distinguishing of scalar field models of dark energy with different Lagrangians and time variable equation of state parameter by available observational data is analyzed. The multicomponent cosmological models with the…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-17 Bohdan Novosyadlyj , Olga Sergijenko , Stepan Apunevych

We conduct a Bayesian analysis of recent observational datasets, specifically the Cosmic Chronometers (CC) dataset and Pantheon samples, to investigate the evolution of the EoS parameter in dark energy models. Our study focused on the…

Cosmology and Nongalactic Astrophysics · Physics 2023-09-29 N. Myrzakulov , M. Koussour , Alnadhief H. A. Alfedeel , Amare Abebe

We introduce a set of two-parameter models for the dark energy equation of state (EOS) $w(z)$ to investigate time-varying dark energy. The models are classified into two types according to their boundary behaviors at the redshift…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 Qing-Jun Zhang , Yue-Liang Wu

In this paper we investigate non-compact FRW type Kaluza-Klein cosmology coupled with 5D energy-momentum tensor. The field equations are solved by taking gravitational and cosmological constants as a function of time $t$. We use…

General Physics · Physics 2011-06-10 M. Sharif , Farida Khanum

We constrain the parameters of dynamical dark energy in the form of a classical or tachyonic scalar field with barotropic equation of state jointly with other cosmological ones using the combined datasets which include the CMB power spectra…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 Olga Sergijenko , Ruth Durrer , Bohdan Novosyadlyj

One of the main aims in the next generation of precision cosmology experiments will be an accurate determination of the equation of state (EOS) for the dark energy (DE). If the latter is dynamical, the resulting barotropic index \omega…

Astrophysics · Physics 2009-11-13 Joan Sola , Hrvoje Stefancic

We study the late-time evolution of the Universe where dark energy (DE) is presented by a barotropic fluid on top of cold dark matter (CDM). We also take into account the radiation content of the Universe. Here by the late stage of the…

General Relativity and Quantum Cosmology · Physics 2015-07-24 Ozgur Akarsu , Mariam Bouhmadi-López , Maxim Brilenkov , Ruslan Brilenkov , Maxim Eingorn , Alexander Zhuk

We propose a two parameter generalization for the dark energy equation of state (EOS) $w_X$ for thawing dark energy models which includes PNGB, CPL and Algebraic thawing models as limiting cases and confront our model with the latest…

Cosmology and Nongalactic Astrophysics · Physics 2014-05-09 Debabrata Adak , Debasish Majumdar , Supratik Pal

Constraining the dark energy equation of state, $w_x(z)$, is one of the main issues of current and future cosmological surveys. In practice, this requires making assumptions about the evolution of $w_x$ with redshift $z$, which can be…

General Relativity and Quantum Cosmology · Physics 2019-07-29 Celia Escamilla-Rivera , Salvatore Capozziello

The equation of state parameter is a significant method for characterizing dark energy models. We investigate the evolution of the equation of state parameter with redshift using a Bayesian analysis of recent observational datasets (the…

General Relativity and Quantum Cosmology · Physics 2023-02-15 Gaurav N. Gadbail , Simran Arora , P. K. Sahoo

In this present work, we try to build up a cosmological model using a non-canonical scalar field within the framework of a spatially flat FRW space-time. In this context, we have considered four different parametrizations of the equation of…

General Relativity and Quantum Cosmology · Physics 2015-06-03 Abdulla Al Mamon , Sudipta Das

The present paper reports a study on the cosmological consequences arising from reconstructing $f(T)$ gravity through new holographic-polytropic dark energy. We assume two approaches, namely a particular form of Hubble parameter $H$ and a…

General Relativity and Quantum Cosmology · Physics 2016-11-01 Surajit Chattopadhyay , Abdul Jawad , Shamaila Rani